FORM 6-K
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
Report of Foreign Issuer
Pursuant to Rule 13a-16 or 15d-16 of
the Securities Exchange Act of 1934
For the month of October, 2026
Commission File Number: 001-12518
Banco Santander, S.A.
(Exact name of registrant as specified in its charter)
Ciudad Grupo Santander
28660 Boadilla del Monte (Madrid) Spain
(Address of principal executive office)
Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F:
| Form 20-F | X |
Form 40-F |
Banco Santander, S.A.
TABLE OF CONTENTS
Item |
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| 1 | Report of Other Relevant Information dated October 22, 2026 |
Item 1
Banco Santander, S.A. (the “Bank” or “Banco Santander”), in compliance with the Securities Market legislation, hereby communicates the following:
OTHER RELEVANT INFORMATION
Reference is made to our notice of inside information of 10 August 2026 (official registry number 3336) (the “Buyback Commencement Communication”), relating to the buyback programme of own shares (the “Buyback Programme”) approved by the Board of Directors of Banco Santander.
Pursuant to article 5 of Regulation (EU) no. 596/2014 on Market Abuse of 16 April 2014, and articles 2.2 and 2.3 of Commission Delegated Regulation (EU) 2016/1052, of 8 March 2016, the Bank informs of the transactions carried out over its own shares between 15 and 21 October (both inclusive).
The cash amount of the shares purchased to 21 October 2026 as a result of the execution of the Buyback Programme amounts to 1,474,221,281 Euros, which represents approximately 80.8% of the maximum investment amount of the Buyback Programme. The programme was announced together with its other characteristics through the Buyback Commencement Communication. With these purchases, the Bank has repurchased approximately 18.6% of its outstanding shares as of 2021.
| Date | Security | Transaction | Trading venue | Number of shares | Weighted average price (€) |
| 15/10/2026 | SAN | Purchase | XMAD | 2,100,000 | 11.9888 |
| 15/10/2026 | SAN | Purchase | CEUX | 296,874 | 11.9951 |
| 15/10/2026 | SAN | Purchase | TQEX | 41,993 | 11.9717 |
| 15/10/2026 | SAN | Purchase | AQEU | 161,133 | 11.9975 |
| 16/10/2026 | SAN | Purchase | XMAD | 500,000 | 12.0517 |
| 19/10/2026 | SAN | Purchase | XMAD | 4,000,000 | 11.7909 |
| 19/10/2026 | SAN | Purchase | CEUX | 1,127,932 | 11.7768 |
| 19/10/2026 | SAN | Purchase | TQEX | 336,267 | 11.8032 |
| 19/10/2026 | SAN | Purchase | AQEU | 535,801 | 11.7806 |
| 20/10/2026 | SAN | Purchase | XMAD | 4,200,000 | 11.7270 |
| 20/10/2026 | SAN | Purchase | CEUX | 1,769,587 | 11.6860 |
| 20/10/2026 | SAN | Purchase | TQEX | 342,357 | 11.6666 |
| 20/10/2026 | SAN | Purchase | AQEU | 688,056 | 11.6942 |
| 21/10/2026 | SAN | Purchase | XMAD | 2,664,002 | 11.8742 |
| 21/10/2026 | SAN | Purchase | CEUX | 147,445 | 11.7673 |
| 21/10/2026 | SAN | Purchase | TQEX | 68,651 | 11.7577 |
| 21/10/2026 | SAN | Purchase | AQEU | 119,902 | 11.7666 |
| TOTAL | 19,100,000 |
Issuer name: Banco Santander, S.A. - LEI 5493006QMFDDMYWIAM13
Reference of the financial instrument: ordinary shares - Code ISIN ES0113900J37
Detailed information of the transactions carried out within the referred period is attached as Annex I.
Boadilla del Monte (Madrid), 22 October 2026
1
ANNEX I
Detailed information on each of the transactions carried out within the context of the Buy-back Programme between 15/10/2026 and 21/10/2026 (both inclusive)
(https://www.santander.com/content/dam/santander-com/es/documentos/cumplimiento/do-anexo-i-15-a-21-octubre-2026-es.pdf)
2
SIGNATURE
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.
| Banco Santander, S.A. | |||||
| Date: | October 22, 2026 | By: | /s/ Pedro de Mingo Kaminouchi | ||
| Name: | Pedro de Mingo Kaminouchi | ||||
| Title: | Head of Corporate Compliance | ||||